1. Field of the Invention
The invention relates to interpolation of color signals, and more specifically, to restoration of Green uniformity of RGB Bayer sensors.
2. Description of the Related Art
RGB Bayer sensors have an alternating color pattern of rows having RGRG etc., colored pixels, and GBGB etc., colored pixels. In the vertical direction of a xe2x80x98Redxe2x80x99 column, a Green pixel has only Red pixels as vertically neighboring pixels, while in a xe2x80x98Bluexe2x80x99 column, a Green pixel has only Blue pixels as vertically neighboring pixels. Depending on the quality of the vertical color separation of the sensor, the Green pixels can be modulated by the amount of electron charge in the Red and Blue pixels. If so, then for certain colored scenes, this may result in a visible column-wise Green non-uniformity. A nice example is a highlighted Cyan color, which, theoretically has no Red but only Blue and Green. This will result in a different Green for the Red and Blue columns, which can be visible on a display or on a printout especially because of its regularity. A stylistic example of the column-wise modulation of Green by the electron charges of the Red and Blue pixels is shown in FIG. 1.
It is, inter alia, an object of the invention to reduce this Green non-uniformity without losing resolution. To this end, a first aspect of the invention provides a method and a device for interpolating an output color signal. A second aspect of the invention provides a camera including such a device.
In a method of interpolating an output color signal of a given color in dependence on an input signal having first values of the given color which are influenced by a first other color, and second values of the given color which are influenced by a second other color, in accordance with a primary aspect of the present invention, an intermediate color signal is interpolated at positions where no signal of the given color is present, an average value of the given color is generated in dependence upon both the first and second values, and the output color signal is furnished in dependence upon both the intermediate color signal and the average value.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.